How can do asp.net mvc5 caching to hard drive?

Question

Currently I am working on an .net MVC 5 project and I need to cache some data on hard drive. How can I cache data and pages on server's hard drive?

Answer 1

You can implement custom OutputCacheProvider.

public class FileCacheProvider : OutputCacheProvider
{
    private string _cachePath;

    private string CachePath
    {
        get
        {
            if (!string.IsNullOrEmpty(_cachePath))
                return _cachePath;

            _cachePath = ConfigurationManager.AppSettings["OutputCachePath"];
            var context = HttpContext.Current;

            if (context != null)
            {
                _cachePath = context.Server.MapPath(_cachePath);
                if (!_cachePath.EndsWith("\\"))
                    _cachePath += "\\";
            }

            return _cachePath;
        }
    }

    public override object Add(string key, object entry, DateTime utcExpiry)
    {
        Debug.WriteLine("Cache.Add(" + key + ", " + entry + ", " + utcExpiry + ")");

        var path = GetPathFromKey(key);

        if (File.Exists(path))
            return entry;

        using (var file = File.OpenWrite(path))
        {
            var item = new CacheItem { Expires = utcExpiry, Item = entry };
            var formatter = new BinaryFormatter();
            formatter.Serialize(file, item);
        }

        return entry;
    }

    public override object Get(string key)
    {
        Debug.WriteLine("Cache.Get(" + key + ")");

        var path = GetPathFromKey(key);

        if (!File.Exists(path))
            return null;

        CacheItem item = null;

        using (var file = File.OpenRead(path))
        {
            var formatter = new BinaryFormatter();
            item = (CacheItem)formatter.Deserialize(file);
        }

        if (item == null || item.Expires <= DateTime.Now.ToUniversalTime())
        {
            Remove(key);
            return null;
        }

        return item.Item;
    }

    public override void Remove(string key)
    {
        Debug.WriteLine("Cache.Remove(" + key + ")");

        var path = GetPathFromKey(key);

        if (File.Exists(path))
            File.Delete(path);
    }

    public override void Set(string key, object entry, DateTime utcExpiry)
    {
        Debug.WriteLine("Cache.Set(" + key + ", " + entry + ", " + utcExpiry + ")");

        var item = new CacheItem { Expires = utcExpiry, Item = entry };
        var path = GetPathFromKey(key);

        using (var file = File.OpenWrite(path))
        {
            var formatter = new BinaryFormatter();
            formatter.Serialize(file, item);
        }
    }

    private string GetPathFromKey(string key)
    {
        return CachePath + MD5(key) + ".txt";
    }

    private string MD5(string s)
    {
        var provider = new MD5CryptoServiceProvider();
        var bytes = Encoding.UTF8.GetBytes(s);
        var builder = new StringBuilder();

        bytes = provider.ComputeHash(bytes);

        foreach (var b in bytes)
            builder.Append(b.ToString("x2").ToLower());

        return builder.ToString();
    }
}

and register your provider in web.config

<appSettings>
  <add key="OutputCachePath" value="~/Cache/" />
</appSettings>

<caching>
  <outputCache defaultProvider="FileCache">
    <providers>
      <add name="FileCache" type="MyCacheProvider.FileCacheProvider, MyCacheProvider"/>
    </providers>
  </outputCache>
</caching>

Answer 2

I did get Alexander's answer to work, but I'm going to add a few things here I learned on the way. It is using:

using System.Security.Cryptography;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using System.Diagnostics;
using System.Web.Caching;

I needed to add this class, and it has to be serializable or it throws an error:

[Serializable]
public class CacheItem
{
    public DateTime Expires { get; set; }
    public object Item { get; set; }
}

I had to change the web.config entry to this, because the answer seems to be referencing a namespace that isn't in the code. Not exactly sure on that, and I couldn't find any documentation on this tag:

<outputCache defaultProvider="FileCache">
    <providers>
      <add name="FileCache" type="FileCacheProvider"/>
    </providers>
  </outputCache>

And this one might be kind of obvious, but when you start testing and using it, make sure that expiration time is in UTC time:

DateTime expireTime = DateTime.UtcNow.AddHours(1);